Difference between revisions of "Aptostichus chavezi"

Latest revision as of 09:53, 20 December 2012

Taxonavigation

Ordo: Araneae
Familia: Euctenizidae
Genus: Aptostichus

Name

Aptostichus chavezi Bond, 2012 sp. n. – Wikispecies link – UFW Trapdoor Spider’ ZooBank link – Pensoft Profile

Types

Male holotype (AP562) from California, Tulare Co., Ash Mountain, Kaweah Power Station #3, 64km NE Visalia, 36.488, -118.8375, elev. 460m, coll. D. Burdick 3.iii.1983; female paratype (MY3774) from California, Tulare Co., HWY 245, ~22.4km N of Woodlake, near confluence of Cottonwood Creek & Rattlesnake Creek, 36.5856, -119.12201, elev. 380m, coll. M. Hedin, D. Leavitt, J. Satler, J. Starrett 26.iii.2009; deposited in AUMNH.

Etymology

The specific epithet is a patronym in honor of labor and civil rights leader César Chávez (1927–1993).

Diagnosis

Male of Aptostichus chavezi can be distinguished from all other Sierra group species on the basis of a unique tibia I spination pattern that is most similar to that of its hypothesized and geographically proximate sister species Aptostichus dorothealangeae. Aptostichus chavezi males can be differentiated from Aptostichus dorothealangeae males by having a far greater number of spines on the prolateral surface of tibia I (Fig. 348; 26 vs. 12–16). Females of Aptostichus chavezi and Aptostichus dorothealangeae are very similar in appearance, however, Aptostichus chavezi specimens are, on average, larger (Cl 5.28 vs. 4.56) and tend to have more patella III prolateral spines (11-20 vs. 7-10). The known distributions of these two species do not overlap.

Description of male holotype

Specimen preparation and condition. Specimen presumed collected from pitfall trap, preserved in 70%EtOH. Coloration slightly faded. Pedipalp, leg I right side removed, stored in vial with specimen; leg I left side missing. General coloration. Carapace, chelicerae, legs yellowish red 5YR 4/6. Abdomen brown, 7.5YR 4/3; distinct dorsal mottled striping pattern. Cephalothorax. Carapace 4.40 long, 3.47 wide, lightly hirsute with thin white setae intermingled with thin black setae, stout black bristles along fringe; surface smooth, pars cephalica elevated. Fringe, posterior margin with black bristles. Foveal groove deep, strongly recurved. Eyes on low mound. AER, slightly procurved, PER recurved. PME, AME subequal diameter. Sternum moderately setose, STRl 2.45, STRw 1.84; elongate. Posterior sternal sigilla small, positioned laterally, anterior sigilla pairs small, oval, marginal. Chelicerae with distinct anterior tooth row comprising 5 teeth, posterior margin with single row of small denticles. Palpal endites with patch of small cuspules on proximal, inner margin, labium with 2 cuspules, LBw 0.58, LBl 0.27. Rastellum consists of 4 stout spines not on prominent mound. Abdomen. Setose, heavy black setae intermingled with fine black setae. Legs. Leg I: 4.05, 3.04, 3.44, 2.40, 0.00; leg IV: 4.20, 2.64. Light tarsal scopulae on all legs, light scopulae on distal aspect metatarsus I. Tarsus I with single, slightly staggered row of 10 trichobothria. Leg I spination pattern illustrated in Figures 347, 348; TSp 14, TSr 4 , TSrd 1. Tibia I long relative to femur I, with numerous prolateral spines, few retrolateral spines. Distal retrolateral spine patch absent, single distal spine. Metatarsus not anteverted, lacks distinct mid–ventral mating apophysis, proximal excavation. Metatarsus, tarsus I elongate. Pedipalp. Palpal tibia intermediate in length, width slightly less than half-length; PTw 0.83, PTl 1.88, Bl 0.71. Retrolateral surface bears 1 large spine (Fig. 349), surrounded by few smaller spines. Pyriform shaped palpal bulb short (Bl/Cl 16.14); embolus base stout, but tip very thin, slight midpoint curvature, not serrated distally.
Variation. Known only from the type specimen.

Description of female paratype

Specimen preparation and condition. Female collected live from burrow, prepared in same manner as male holotype. Genital plate removed, cleared in trypsin, stored in microvial with specimen; legs II-IV right-hand side removed for tissue storage. Color slightly faded. Carapace, legs, chelicerae, yellowish red 5YR 4/6; purplish tinting at carapace fringe (Fig. 351). Abdomen brown, 7.5YR 4/3; distinct dorsal mottled striping pattern. Cephalothorax. Carapace 6.06 long, 5.20 wide, glabrous with few fine black setae; generally smooth surface, pars cephalica moderately elevated. Fringe lacks setae. Foveal groove deep, slightly recurved. Eye group slightly elevated on low mound. AER slightly procurved, PER slightly recurved. PME-AME subequal diameter. Sternum elongate, moderately setose, STRl 3.40, STRw 2.73. Three pairs of sternal sigilla anterior pairs small, oval, marginal, posterior pair small, laterally positioned. Chelicerae anterior tooth row comprising 6 teeth with posterior margin denticle patch. Palpal endites with 22 cuspules concentrated at the inner promargin posterior heel; labium with 3 cuspules, LBw 1.02, LBl 0.51. Rastellum comprises of 6 stout spines not positioned on mound; fringe of short spines along distal promargin extending upward from rastellum. Abdomen. Moderately setose. PLS all 3 segments with spigots. Terminal segment 1/2 length of medial segment, 2 enlarged spigots visible at tip. PMS single segment, with spigots, short with rounded terminus. Walking legs. Anterior two pairs noticeably more slender than posterior pairs. Leg I 13.17 long. Tarsus I with single staggered row of 12 trichobothria. Legs I, II, with moderately heavy scopulae on tarsi, metatarsi; light scopulae on tarsi III, IV. PTLs 17, TBs 2. Preening combs on retrolateral distal surface (at tarsus-metatarsus joint) of metatarsus IV, III, highly reduced to absent. Spermathecae. Heavily sclerotized, 2 simple spermathecal bulbs on short neck, arranged on small spermathecal base (Fig. 350).
Variation (5). Cl 4.75-6.06, 5.28±0.25; Cw 3.88-5.20, 4.25±0.25; STRl 2.78-3.47, 3.12±0.13; STRw 2.00-2.73, 2.32±0.12; LBw 0.77-1.02, 0.92±0.05; LBl 0.36-0.51, 0.42±0.03; Leg I: 10.42-13.17, 11.39±0.56; ANTd 5-6, 5.8±0.2; PTLs 11-20, 15.20±1.56; TBs 2-4, 3.4±0.4.

Material examined:

United States: California: Fresno Co.: Elwood Rd, above Tretten Canyon, N Hwy 180, 36.7692, -119.25581, 470m, M Hedin, D Leavitt, J Satler, J Starrett 26.iii.2009 [MY3773, 1juv, AUMNH]; Hopewell Rd, N of Clingans jct, Hwy 180, 36.7737, -119.17191, 710m, M Hedin, D Leavitt, J Satler, J Starrett 26.iii.2009 [MY3772, 1juv, AUMNH]; Tuolumne Co.: 5km W Columbia, Crystal Palace Cave, 38.035, -120.44945, 360m, W Elliott, A Grubbs, S Winterath 21.ii.1977 [AP557, 1♀, AMNH]; Tulare Co.: Hwy 198 S end Lake Kaweah, 36.3958, -118.94781, 253m, J Bond 8.v.1997 [AP782, 783 2♀, CAS; AP784, 786, 787, 2♀, 1juv, AUMNH]; Ash Mountain, Kaweah Power Station #3 (64km NE Visalia), 36.488, -118.8375, 460m, D Burdick 10.vii.1983 [AP561, 562, 1juv, CAS], 3.iii.1983 [AP562, 1♂, CAS]; 9.6km [road] S Badger on Road J21, 36.5783, -119.01115, 524m, W Icenogle 17.x.1973 [AP554, 1♀, AMNH]; Hwy 245, ~22.4km N of Woodlake, near confluence Cottonwood Crk & Rattlesnake Crk, 36.5856, -119.1221, 380m, M Hedin, D Leavitt, J Satler, J Starrett 26.iii.2009 [AP1248, MY3774, 2♀, AUMNH].

Distribution and natural history

Aptostichus chavezi is distributed predominantly throughout Tulare and Fresno Counties (Fig. 34) in the Sierra Nevada foothills. The locality further to the north in Fresno County, not predicted in the DM (Fig. 35) may be a fifth, closely related Sierra group species. Because only a single specimen is known I have chosen to be conservative and include this specimen as part of the Aptostichus chavezi hypothesis until males become available. The habitat type throughout this species range is characterized as Sierran steppe, mixed and coniferous forest. Based on the single male specimen, it appears that males are late winter dispersers (March).

Conservation status

Based on its widespread distribution and general abundance in collections, this species would likely be considered secure.

Species concept applied

Morphological.

Original Description

• Bond, J; 2012: Phylogenetic treatment and taxonomic revision of the trapdoor spider genus Aptostichus Simon (Araneae, Mygalomorphae, Euctenizidae) ZooKeys, 252: 1-209. doi

Images

Figures 31–38. Standard light microscopy views of female an Aptostichus simus specimen (MY3432). 31 side view 32 ventral view, sternum 33 dorsal view, carapace 34–35 eye group, dorsal and lateral views 36 leg I prolateral view 37 leg IV retrolateral view 38 palpal endite.  Map 34, 35. Distribution of Sierra group species. 34 known distribution of Aptostichus dorothealangeae, Aptostichus chavezi, Aptostichus huntington, and Aptostichus sierra 35 predicted distribution of Aptostichus chavezi; cooler colors–blue shades–represent areas of high probability of occurrence, warmer colors–yellow and orange shades–represent areas of low probability of occurrence.  Figures 347–351. Aptostichus chavezi sp. n. from Tulare County. 347–349 male holotype (AP562); scale bars = 1.0mm 347 retrolateral aspect, right leg I [806401] 348 prolateral aspect, right leg I [806405] 349 retrolateral aspect, pedipalp [806407] 350 cleared spermathecae (AP1248) [806408]; scale bar = 0.1mm 351 female paratype (MY3774) from Tulare County, photographed in life.